Jamieson, Fausset and Brown on 2 Samuel 19:5

5. Thou hast shamed ... the faces of all thy servants--by withdrawing thyself to indulge in grief, as if their services were disagreeable and their devotion irksome to thee. Instead of hailing their return with joy and gratitude, thou hast refused them the small gratification of seeing thee. Joab's remonstrance was right and necessary, but it was made with harshness. He was one of those persons who spoil their important services by the insolence of their manners, and who always awaken a feeling of obligation in those to whom they render any services. He spoke to David in a tone of hauteur that ill became a subject to show towards his king.